A backplane is a group of electrical connectors in parallel with each other so that each pin of each connector is linked to the same relative pin of all the other connectors forming a computer bus. It may be used as a backbone to connect several printed circuit boards together to make up a complete computer system.
Some backplanes may be constructed with slots for connecting to devices on both sides. These may be referred to as midplanes. The ability to plug cards into either side of a midplane is often useful in systems such as network switches. For example, a midplane may be used where one side of a chassis accepts system processing cards and the other side of the chassis accepts network interface cards.
As signaling rates of circuits increase, the insertion loss budgets of the electrical channels (e.g., Director Class switch) decrease. For example, a line card switch port may be connected to other line card switch ports through the midplane. In order to maintain signal integrity attributes of an electrical channel, the insertion loss of individual components that comprise the electrical channel should be reduced. There are general needs for reducing insertion loss of network switches.